JPH0456A - Control device for continuously variable transmission - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to electronically controlling secondary pressure and speed change using a valve equipped with a current-proportional electromagnetic linear solenoid in a belt-type continuously variable transmission for a vehicle. The present invention relates to a device, and specifically relates to dither correction when dithering a solenoid current.

[Conventional technology]

Conventionally, it has been possible to control the secondary pressure and primary pressure by installing a linear solenoid in each control valve of the hydraulic control system of this type of continuously variable transmission, and operating the control valve by passing an analog solenoid current. This has been proposed by the applicant (Japanese Patent Application No. 28718). In valve operation using such an analog solenoid current, in order to reduce the hysteresis of the valve, dither that periodically changes with a predetermined amplitude is applied to the solenoid current.

In this case, the dither current swings equally above and below the solenoid current, and therefore, the average current obtained by applying the dither current to the solenoid current can be the same as the solenoid current. The pulsating flow of solenoid current causes the control valve to operate without constant vibration, thereby reducing valve hysteresis.

[Problem to be solved by the invention]

By the way, in the dithering process of the solenoid current,
The rise characteristic of the dither current applied in a pulsed manner has a first-order lag due to the time constant of the circuit. It is used under conditions in which the coil resistance changes with the oil temperature of the transmission, and the control unit output voltage changes with the balance between power supply and consumption in the vehicle. For this reason, the rise characteristics of the current are always different due to the influence of the above-mentioned changing factors, and there is a risk that the average current will deviate from the target solenoid current and the accuracy of hydraulic control will be impaired.

The present invention has been made in view of the above, and its purpose is to correct various changing factors so that the average current always matches the target solenoid current in dither processing of the solenoid current. An object of the present invention is to provide a control device for a continuously variable transmission that can improve control accuracy.

[Means to solve the problem]

In order to achieve the above object, the control device for a continuously variable transmission of the present invention applies a pulsed dither to a solenoid current by a control unit, and applies a dither current to a solenoid of a control valve of a hydraulic control system of a continuously variable transmission. In the control system that operates by supplying the dither current to the solenoid current, the control system includes an integral value calculation means for calculating the value of the deviation integral of the dither current with respect to the solenoid current, and a correction amount calculation means for calculating the dither correction amount by the sum of the integral values and outputting the dither correction amount to the dither application means. means.

[For production]

Based on the above configuration, when a dither current consisting of a solenoid current and a dither is supplied to a current proportional solenoid of a control valve of a continuously variable transmission hydraulic control system, the state of the average current accompanying the rise of the dither current is the deviation integral. The sum of the values is constantly checked, and when the average current subtracts from the solenoid current, the dither duty ratio is corrected so that both match.

Therefore, even if the rise characteristics of the dither current change due to various factors, the average current matches the solenoid current, and the control valve is always operated accurately.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

Referring to FIG. 2, an outline of the drive system of a continuously variable transmission with a lock-up converter will be described. Reference numeral 1 is an engine, which includes a crankshaft 2, a torque converter device 31, a forward/reverse switching device 4. Continuously variable transmission 5 and differential device 6
The transmission is configured sequentially.

In the torque converter device 3, the crankshaft 2 is connected to a converter cover 11 and a pump impeller 12a of a torque converter 12 via a drive plate 10. A turbine runner 12b of the torque converter 12 is connected to a turbine shaft 13, and a stator 12c is guided by a one-way clutch 14. The lock-up clutch 15 integrated with the tabine runner 12b is connected to the drive plate 1.
0, and transmits engine power via the torque converter 12 or lock-up clutch 15.

The forward/reverse switching device 4 has a double binion planetary gear I6, inputs the turbine shaft 13 to the sun gear lea, and outputs the input from the carrier 16b to the primary shaft 2o. A forward clutch I7 is provided between the sun gear 1.6a and the carrier IBb, a reverse brake 18 is provided between the ring gear 16c and the case, and when the forward clutch 17 is engaged, the planetary gear 1B is integrated with the turbine shaft 13. It is directly connected to the primary shaft 2o. Furthermore, the reverse brake 18 is engaged to output reversed power to the primary shaft 20, and the forward clutch 17 and reverse brake 18 are released to free the planetary gear 16.

The continuously variable transmission 5 has a hydraulic cylinder 21 on a primary shaft 20.
The primary pulley 22 with variable pulley spacing has
A secondary pulley 25 having a hydraulic cylinder 24 is similarly provided on the secondary shaft 23, and the primary pulley 2
A drive belt 26 is also wound between the drive belt 2 and the secondary pulley 25. Here, the pressure receiving area of the primary cylinder 2 is set to be larger, and the primary pressure of the primary cylinder 2 is used to pull the primary pulley 22 of the drive belt 26. The winding around the secondary pulley 25 is configured to change the diameter ratio so as to be continuously variable.

In the differential device 6, an output shaft 28 is connected to a secondary shaft 23 via a pair of transmission gears 27.
The drive gear 29 of this output shaft 28 is the final gear 3.
meshes with 0. And the differential device 31 of the final gear 30
is connected to left and right wheels 33 via an axle 32.

On the other hand, in order to obtain a hydraulic pressure source for controlling the continuously variable transmission, an oil pump 34 is disposed adjacent to the torque converter 12.
This oil pump 34 is connected to the converter cover 11 by a pump drive shaft 35, so that the pump is always driven by engine power and oil pressure is generated.

In the continuously variable transmission 4, since the hydraulic pressure is controlled over a wide range of high and low levels, the oil pump 34 is of a roller vane type, for example, and has a plurality of sets of suction and discharge ports, and is configured as a variable displacement type.

Next, a continuously variable transmission control system will be described as a hydraulic control system.

First, an oil passage 41 from the oil pump 34 communicating with the oil pan 40 communicates with the secondary pressure control valve 50 to generate a predetermined secondary pressure Ps.
The oil is constantly supplied to the secondary cylinder 24 through the oil passage 42. The secondary pressure Ps is guided to the primary pressure control valve 60 via the oil passage 43, and is supplied to and discharged from the primary cylinder 21 through the oil passage 44, thereby generating the primary pressure Pp.

The secondary pressure control valve 50 is a proportional electromagnetic relief valve, and a solenoid current Is is supplied to the proportional solenoid 51 by a control unit 70. Then, the solenoid current I
The electromagnetic force caused by s, the hydraulic reaction force of the secondary pressure Ps, and the spring force (not shown) act on a spool (not shown) opposingly, and the pressure is adjusted so that these are balanced. That is, the set pressure is made variable by the solenoid current Is, and the secondary pressure P is adjusted in a 1:1 proportional relationship to the solenoid current Is.
s.

The primary pressure control valve 60 is a proportional electromagnetic relief valve, and like the secondary pressure control valve 50, a proportional solenoid 61 is used.
A solenoid current Ip is supplied by the control unit 70. Then, the electromagnetic force caused by the solenoid current 1p, the hydraulic reaction force of the primary pressure Pp, and the spring force (not shown) act in opposition on the spool (not shown), and the set pressure is made variable by the solenoid current Ip, so that the solenoid current 1
The primary pressure Pp is controlled in a one-to-one proportional relationship to p.

In FIG. 1, an electronic control system including a control unit 70 will be described.

First, the control unit 70 calculates a target secondary pressure Pss according to various driving and running conditions, and adjusts the solenoid current Is in a 1:1 relationship with respect to the target secondary pressure Pss.
is obtained in an analog manner and instructed to the output section 71. Further, a dither D is applied to the output section 71 by a dither application section 72, so that a periodically changed dither current ID flows from the output section 71 to the proportional solenoid 51.

Here, as shown in Fig. 3(a), the dither D is pulse-like with a constant period, and the solenoid current Is is as shown in Fig. 3(b).
), and the dither current is the sum of the two. As shown in FIG. 3(C), the current dither current ■ changes periodically up and down around the current Is. The average current ■− is set for And the dither current ■ in this case. has a characteristic that rises with a first-order lag due to the time constant of the circuit, and this rise etc. changes due to fluctuations in the coil resistance.

Therefore, in order to always match the average current 1+ with the solenoid current Is in the dither current ID, the duty ratio e of the dither D must be corrected so that the integrated deviation value for the solenoid current Is in one dither period becomes zero. Bye. Therefore, the solenoid current Is of the control unit 70
and the dither current ID of the output section 71, and calculates the integral value of the upper and lower portions of the dither current ID with respect to the solenoid current Is in one dither cycle.

That is, as shown in FIG. 4, the upper portion Sl of the dither current IO
and the lower portion 52 S3 are calculated as follows.

These integral values S, , S2. S3 is inputted to the correction amount calculating section 74, and the dither duty ratio correction amount Δe is calculated according to the total value S (S-5, -52S3). That is, S>
If S is 0, -Δe is determined, and if S<0, +Δe is determined and output to the dither applying section 72 (FIG. 5).

Next, the operation of the continuously variable transmission control device configured in this manner will be described.

First, during engine operation, when engine power is manually applied to the primary shaft 20 of the continuously variable transmission 5 via the torque converter half 21 and the forward/reverse switching device 4, the primary shaft 20 of the continuously variable transmission 5 is applied to the primary shaft 20 of the continuously variable transmission 5. Secondary pulley 25. Then, the power shifted by the heald 26 is outputted to the secondary shaft 23, and the shifting power is further transmitted to the wheels 33 to drive the vehicle. At this time, the control unit 70 controls the solenoid current according to the target secondary pressure Pss. Is is set, dither D is applied by the dither applying section 72 at the output section 71, and the solenoid current Is
The dither current changes periodically at the same level as■. flows to the proportional solenoid 51. Therefore, the secondary pressure control valve 5
0 operates proportionally without vibration due to the dither current, and performs pressure regulation control so that the secondary pressure Ps matches the target value.

On the other hand, the dither current ■ from the output section 71 is generated. is input to the integral value calculation unit 73 together with the solenoid current Is, the deviation integral value for the solenoid current Is is calculated, and the total value S is used in the correction amount calculation unit 74 to calculate the average current 1 m of the dither current ID as the solenoid current. It is determined whether or not it matches Is. Therefore, for example, the rising edge of the dither current ID changes due to the influence of factors such as an increase in coil resistance due to low oil temperature or a decrease in unit output voltage. As shown in Fig. 4, if the solenoid current is lower than Is, the duty ratio e of dither D will be +Δe, and the difference in Fig. 5(a) will increase.
The increase is corrected as shown in b). Therefore, the upper part S1 of the dither current generator becomes larger than the lower part S2, and the level of the average current Im becomes higher, so that the solenoid current Is and the average current Its match, and the proportional solenoid 51 has a solenoid current Is. Strictly corresponding dither current ID or current,
Valve operates accurately. On the other hand, if the average current In deviates from the solenoid current Is, the dither duty ratio e is corrected to decrease as shown in FIG. controlled as follows.

Although the current Is of the secondary proportional solenoid 51 has been described above, the current Is of the primary solenoid 61 can be similarly applied to the current Is of the primary solenoid 61.

As another embodiment of the present invention, in the correction amount calculating section 74, the duty ratio e of the dither D is kept constant as shown in FIG. 5(d), and the correction amount of the upper amplitude Au or the F side amplitude AD is
It may be determined such that the sum of the integral values S becomes zero.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto.

〔Effect of the invention〕

As described above, according to the present invention, the control valve of the hydraulic control system of a continuously variable transmission has a current proportional solenoid, and in an electronic control system in which a pulsed dither is applied to the solenoid current, the dither Since the state of the current is constantly checked and corrected, when the dither current changes due to fluctuations in transmission oil temperature, unit output voltage, etc., the dither current can be optimized and control accuracy can be improved.

Furthermore, since the correction is performed using the total value of the deviation integral of the dither current with respect to the solenoid current, the average of the dither current always matches the solenoid current, allowing accurate valve operation.

Furthermore, by correcting the duty ratio or amplitude of the dither, the average value of the current can be easily and appropriately changed to match the solenoid current.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the main electronic control system showing an embodiment of a control device for a continuously variable transmission according to the present invention, FIG. 2 is a block diagram of a continuously variable transmission to which the present invention is applied, and FIG. FIG. 4 is a diagram showing the dither and each current; FIG. 4 is a diagram showing the deviation integration state of the dither current; FIG. 5 is a diagram showing the dither correction state and the correction state of other embodiments. 5...Continuously variable transmission, 50...Secondary pressure control valve, 51
゜6I...Proportional solenoid, 60...Primary pressure control valve, 70...Control unit, 71...Output section,
72... Dither application section, 73... Integral value calculation section, 7
4. Correction Amount Calculation Department Patent Applicant Fuji Heavy Industries Co., Ltd. Agent Patent Attorney Jundo Kobashi Patent Attorney Wataru Kokura

Claims (2)

[Claims] (1) In a control system that operates by supplying a dither current obtained by applying pulse-like dither to a solenoid current by a control unit to a solenoid of a control valve of a continuously variable transmission hydraulic control system, the dither current with respect to the solenoid current is A control device for a continuously variable transmission, comprising an integral value calculating means for calculating a value of a deviation integral, and a correction amount calculating means for calculating a dither correction amount based on the sum of the integral values and outputting it to a dither applying means. . (2) The control device for a continuously variable transmission according to claim (1), wherein the integral value calculating means calculates an integral value of a portion above and a portion below the solenoid current of the dither current of one dither period. . (3) The control device for a continuously variable transmission according to claim (1), wherein the correction amount calculation means calculates the correction amount of the dither duty ratio or amplitude so that the sum of the integral values becomes zero. .